DUBAI, United Arab Emirates (AP) — Among those detained in Saudi Arabia, no name carries more power in Western financial markets than Prince Alwaleed bin Talal. The prince, listed by Forbes as the richest Arab with $18.7 billion to his name, long has made big bets in the markets, holding major stakes in companies like Apple and CitiBank. But his arrest now comes after Saudi Arabia hosted a major investment summit in Riyadh at one of the hotels now reportedly holding dozens of princes and former officials detained late Saturday in what authorities described as an anti-corruption campaign.